RS Aggarwal Class 7 Mathematics Twentieth Chapter Mensuration Exercise 20E Solution

RS Aggarwal Class 7 Mathematics Twentieth Chapter Mensuration Exercise 20E Solution

EXERCISE 20E

(1) Find the circumference of a circle whose radius is (i) 28 cm, (ii) 1.4 m.

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(2) Find the circumference of a circle whose diameter is (i) 35 cm, (ii) 4.9 m.

(3) Find the circumference of a circle of radius 15 cm.

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(4) Find the radius of a circle whose circumference is 57.2 cm.  

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(5) Find the diameter of a circle whose circumference is 63.8 m.

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(6) The circumference of a circle exceeds its diameter by 30 cm. Find the radius of the circle.

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(7) The ratio of the radii of two circles is 5 : 3. Find the ratio of their circumference.

(8) How long will a man take to make a round of a circular field of radius 21 m, cycling at the speed of 8 km/h?

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(9) A racetrack is in the form of a ring whose inner circumference is 528 m and the outer circumference is 616 m. Find the width of the track.

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(10) The inner circumference of a circular track is 330 m. The track is 10.5 m wide everywhere. Calculate the cost of putting up a fence along the circle at the rate of Rs 20 per metre.

(11) One circle has a radius of 98 cm and a second concentric circle has a radius of 1 m 26 cm. How much longer is the circumference of the second circle than that of the first?

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(12) A piece of wire is bent in the shape of an equilateral triangle each of whose sides measures 8.8 cm. This wire is rebent to form a circular ring. What is the diameter of the ring?

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(13) A rhombus has the same perimeter as the circumference of a circle. If each side of the rhombus measures 33 cm, find the radius of the circle.

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(14) A wire in the form of a rectangle 18.7 cm long and 14.3 cm wide is reshaped and bent into the form of a circle. Find the radius of the circle so formed.

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(15) A wire is looped in the form of a circle of radius 35 cm. If it is rebent in the of a square, what will be the length of each side of the square?

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(16) A well of diameter 140 cm has a stone parapet around it. If the length of the outer edge of the parapet is 616 cm, find the width of the parapet.

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(17) Find the distance covered by the wheel of a bus in 2000 rotations if the diameter of the wheel is 98 cm.

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(18) The diameter of the wheel of a cycle is 70 cm. How far will it go in 250 revolutions?

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(19) The diameter of the wheel of a car is 77 cm. How many revolutions will it make to travel 121 km?

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(20) A bicycle wheel makes 5000 revolutions in moving 11 km. Find the circumference and the diameter of the wheel.

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(21) The hour and minute hands of a clock are 4.2 cm and 7 cm long respectively. Find the sum of the distance covered by their tips in 1 day.

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